Drug Overdose Case Definitions

Summary of Case Definitions Inclusion and Exclusion Terms and Revisions

 

 

The table below provides a summary of changes made to the drug overdose case definitions by VDH since September 2016.

Month

Description

September 2016 The "Monthly Emergency Department Visits for Overdose by Opioid, Unspecified Substance and Heroin among Virginia Residents" report was first published in September 2016.
July 2017 Three new exclusion terms were added to the Unintentional Overdose by Opioid or Unspecified Substance definition to improve specificity and make it mutually exclusive from the Unintentional Overdose by Heroin definition beginning in the July 2017 report. The exclusion revisions include: “heron” (misspelling of heroin), International Classification of Diseases 9th Revision (ICD-9) code “965.01” and ICD 10th Revision (ICD-10) code “T40.1” referencing heroin overdose. This change resulted in a small decrease in the number of ED visits for unintentional overdose by opioid or unspecified substance than previously reported.
May 2018 Case definition revisions were required beginning in the May 2018 report because of submission of SNOMED Clinical Terms (CT) codes by EDs for discharge diagnosis. Reporting of SNOMED CT codes to VDH began in March 2018. One new exclusion term was added to the Unintentional Overdose by Opioid or Unspecified Substance definition to make it mutually exclusive from the Unintentional Overdose by Heroin definition: SNOMED CT code “295174006” for heroin overdose.
June 2018 VDH revised the case definitions based on guidance from the Centers for Disease Control and Prevention (CDC) as well as findings from a data quality evaluation conducted by VDH.  While the revised case definitions have increased the sensitivity of capturing valid unintentional overdoses among ED visits reported to VDH, the interpretation of the overdose trends and data found in this report are not impacted.

  • Unintentional Overdose by Opioid or Unspecified Substance definition revisions: Inclusion of F11 category ICD-10 codes for opioid use, abuse and dependence, SNOMED CT codes for opioid and opiate overdose, as well as medication and drug brand names referencing opioid analgesics. Exclusion of terms referencing heroin or denial of drug use. The following exclusion terms used in previous versions of the case definition were removed: alcohol, mental health and addiction.
  • Unintentional Overdose by Heroin definition revisions: Inclusion of common street names referencing heroin and SNOMED CT codes for heroin overdose. Exclusion of discharge diagnosis codes and terms referencing suicide ideation and self-harm to match the Opioid and Unspecified Substance case definition. The following exclusion terms used in previous versions of the case definition were removed: alcohol, mental health and addiction.
August 2018
  • Three exclusion terms were added to the Unintentional Overdose by Opioid or Unspecified Substance definition to improve specificity and make it mutually exclusive from the Unintentional Overdose by Heroin definition beginning in the August 2018 report. The exclusion revisions were: International Classification of Diseases 9th Revision (ICD-9) code “965.01” and ICD 10th Revision (ICD-10) code “T40.1X1A” and "T40.1X4A" referencing heroin overdose. This change resulted in a very small decrease in the number of ED visits for Unintentional Overdose by Opioid or Unspecified Substance for historic data in 2015 and 2016.
November 2018
  • Three exclusion terms were added to the Unintentional Overdose by Opioid or Unspecified Substance definition to improve specificity and make it mutually exclusive from the Unintentional Overdose by Heroin definition. The exclusions were: "dope", "speed ball", and "speedball". This change resulted in a very small decrease (N=3 visits) in the number of ED visits for Unintentional Overdose by Opioid or Unspecified Substance in historic data.
January 2019
  • A new case definition was added for All Drug overdose. This case definition includes opioids, heroin, stimulants and other narcotics as well as unspecified overdose where no substance is mentioned.